My main objectives of this research program are to study the mechanisms of viral DNA integration of Adenovirus type 2 and SV40 viruses into the cellular DNA and its subsequent gene expression. The specific plans are: 1. To study the structures of interested Ad2 viral DNA in the infected cells using electron microscope heteroduplex technique. 2. To develop biochemical and biological means for studying the structures of integrated SV40 and Ad2 DNA in the virus transformed cells. 3. To analyze the transcription processes of Ad2 virus in the infected cells using electron microscope technique. 4. To develop methods for studying transcription processes in the SV40 and Ad2 transformed cells.